Tourniquet devices are used for the temporary regulation of the arterial blood flow in the upper and lower extremities of the human body or of an animal body. Known tourniquet devices comprise a tourniquet and a compression cuff that can be connected to it, which is placed on an extremity of a patient and is subsequently inflated so as to reduce the arterial blood flow in the extremity, perhaps to an absolute arrest of the blood flow. The duration and level of the pressure exerted on the extremity by the compression cuff are thereby set according to the specifications of the attending doctor. Typical fields of use for such tourniquet devices are the field of surgical and orthopedic operations, but also in anesthesia (IVRA, “Intravenous Regional Anesthesia”).
The known tourniquet devices have an inflation apparatus for the inflation of the compression cuff connected to the tourniquet device and a control apparatus for the control of the inflation apparatus. So that a tourniquet device to bring about a control of blood flow to various extremities (for example, on the upper arm, on the forearm, on the thigh, or on the calf) and also on different patients can be used, compression cuffs of various sizes can be connected, as a rule, to a tourniquet device. Depending on the circumference of the extremity, a suitable compression cuff is selected, placed on the extremity, and inflated by means of the inflation apparatus of the tourniquet device to a prespecified pressure and over a prespecified duration of the control of the blood flow, so as to limit the blood flow in the extremity and to regulate it during the duration of the blood flow control. The various compression cuffs with different sizes can have a different volume and a different shape, so as to bring about as good as possible an adaptation to the size and shape of the extremity, the type of patient, and the operation procedure to be used.
From WO03/015,641 A1, a tourniquet device with a tourniquet instrument and a large number of tourniquet cuffs that can be connected to it are known, wherein the cuffs have different characteristics and, in particular, different cuff sizes, and each cuff is equipped with a cuff connector that comprises an identification device. The identification device thereby indicates the physical characteristics of the tourniquet cuff, in particular its cuff size. The tourniquet instrument comprises a detection device that is responsive to the identification device of the cuff when a cuff is connected to the tourniquet instrument, so as to detect the physical characteristics of the connected cuff. The identification device is a selection of predetermined colors, wherein each color corresponds to a predetermined physical characteristic of the cuff, for example, a specific cuff size. An optical detection device is located on the tourniquet instrument; it can determine the color of the identification device of a cuff and, in this way, can make a conclusion as to the type and the physical characteristics of the connected cuff. The identification of the physical characteristics of the connected cuff makes possible an optimization of different operating parameters and the emission of warning signals and the storage of operating data. Moreover, the automatic cuff identification prevents an erroneous connection of an unsuitable cuff to the tourniquet instrument.
In practical use, however, this known tourniquet device with an automatic cuff identification proves to be susceptible to error, because with the optical detection device, there may be an erroneous detection of the color of the identification device on the cuff connector. There is also the risk that a false identification device is installed on the cuff connector, which likewise leads to an erroneous identification of the cuff connected to the tourniquet instrument.
Via the automatic cuff identification, the known tourniquet device makes possible the optimization of different operating parameters and the emission of warning signals if an unsuitable cuff has been connected to the tourniquet instrument. An efficient operation of the tourniquet device, which is presented, for example, in as quickly as possible an inflation and release of the compression cuff connected to the tourniquet device, is, however, not yet brought about with the known tourniquet device.